Effect of oxidation annealing on optical properties of YAG:Ce single crystals

Thermal quenching of luminescence in (Lu,Gd,Y)3(Ga, Al)5O12:Ce complex garnet ceramics at high and low temperatures

“…Since Ce 4f ground state position in the energy diagram does not To further investigate the influence of trap concentration on the shape of the NTQ, we used two Lu 0.33 Gd 2.67 Ga 2.5 Al 2.5 O 12 :Ce 3+ ceramic samples prepared under exactly the same conditions but annealed in different atmospheres-i.e., wet FG and O 2 . It is known that treatment in an oxidizing atmosphere can improve luminescence properties of multicomponent garnets and decrease their afterglow and TSL intensity (Boka et al 2015). In our study, the intensity of Ce 3+ luminescence of O 2 annealed ceramic (Fig.…”

Dissimilar behavior of YAG:Ce and LuAG:Ce scintillator garnets regarding Li+ co-doping

“…The positive effect of codoping with Li + on the decay acceleration and on the improvement of the timing resolution was demonstrated also in Cz-grown GAGG:Ce 14 . Finally, it should be mentioned that stable Ce 4+ centers can be created also by air-annealing at high temperatures, as reported for YAG:Ce 15,16 , LuAG:Ce, LuAG:Ce,Mg, YAP:Ce 16 . Summarizing the results, conversion of a part of Ce 3+ ions to Ce 4+ by either divalent or monovalent co-doping and/or air annealing is presently considered as one of the most efficient ways to improve the timing and scintillation yield performances of Cedoped garnet scintillators.…”

YAG:Ce3+ Phosphor: From Micron-Sized Workhorse for General Lighting to a Bright Future on the Nanoscale

“…Some authors suggest that formation of Ce­(IV) during the synthesis is causing lower performance, ,,,,, while others mention lower crystallinity (i.e., more defects) due to low synthesis or calcination temperatures (needed to keep the particles small), ,,,, or a inhomogeneous Ce distribution leading to concentration quenching . In addition, surface defects which arise from the large surface to volume ratio of nanoparticles are also mentioned. ,,,− , The first series of reasons are issues specific for YAG:Ce due to its high crystallization energy and charge transfer effects occurring between possibly coexisting 3+ and 4+ oxidation states of the Ce ions. , These issues should be solved by a careful study of the effect of reaction parameters on the growth kinetics and resulting particle properties, or finding clever ways to anneal the materials while preventing particle growth (Figure ). The latter issue of surface defects is a more fundamental problem of luminescent nanoscale materials in general.…”

“…87,93,97,[102][103][104][105]115 The first series of reasons are issues specific for YAG:Ce due to its high crystallization energy and charge transfer effects occurring between possibly coexisting 3+ and 4+ oxidation states of the Ce ions. 129,130 These issues should be solved by a careful study of the effect of reaction parameters on the growth kinetics and resulting particle properties, or finding clever ways to anneal the materials while preventing particle growth (Figure 11). The latter issue of surface defects is a more fundamental problem of luminescent nanoscale materials in general.…”